Process for the manufacture of neutral polyphosphoric acid esters from p2o5 and orthocarbonic acid esters

ABSTRACT

A PROCES HAS BEEN PROVIDED FOR PRODUCING NEUTRAL POLYPHOSPHORIC ACID ESTER DERIVATIVES WHICH COMPRISES REACTING AN ACID ESTER WITH PHOSPHORUS PENTOXIDE AT A TEMPERATURE WITHIN THE RANGE OF -78*C. TO +140*C., IN THE ABSENCE OF MOISTURE AN IN A MOLE RATION OF ESTER TO PHOSPHORUS PENTOXIDE FROM 0.02 TO 3 MOLES ESTER TO 1 MOLE PHOSPHORUS PENTOXIDE, SAID ACID ESTER BEING DEFINED BY TEH FORMULA   (R&#39;&#39;)M-C(OR)N   WHEREIN M+N=4 IN WHICH FORMULA R REPRESENT A SATURATED, UNSTATURATED, OXALKYLATED, OR HALOGENETED ALIPHATIC RADICAL OF 1 TO 12 CARBON ATOMS, OR AN AROMATIC RADICAL OF 1 TO 12 CARBON ATOMS, AND R&#39;&#39; REPRESENTS A HYDROGEN, A SATURATED, UNSATURATED, OXYALKYLATED, OR HALOGENATED ALIPHATIC OR CYCLOALIPHATIC RADICAL OF 1 TO 12 CARBON ATOMS OR AN AROMATIC RADICAL OF 1 TO 12 CARBON ATOMS. THE COMPOUNDS ARE USEFUL AS CATALYSTS FOR THE PRODUCTION OF POLYACTEALS.

United States Patent F Int. (:1. C07f9/08, 7/02 US. Cl. 260-920 1 ClaimABSTRACT OF THE DISCLOSURE A process has been provided for producingneutral polyphosphoric acid ester derivatives which comprises reactingan acid ester with phosphorus pentoxide at a temperature within therange of 78 C. to +140 C., in the absence of moisture and in a moleratio of ester to phosphorus pentoxide from 0.02 to 3 moles ester to 1mole phosphorus pentoxide, said acid ester being defined by the formulawherein m +n=4 in which Formula R represents a saturated, unsaturated,oxalkylated, or halogenated aliphatic radical of l to 12 carbon atoms,or an aromatic radical of 1 to 12 carbon atoms, and R represents ahydrogen, a saturated, unsaturated, oxalkylated, or halogenatedaliphatic or cycloaliphatic radical of 1 to 12 carbon atoms or anaromatic radical of 1 to 12 carbon atoms. The compounds are useful ascatalysts for the production of polyacetals.

This application is a combination of application Ser. No. 504,187, filedOct. 23, 1965, now abandoned.

The present invention relates to a process for the manufacture ofneutral polyphosphoric acid ester derivatives.

It is known that neutral polyphosphoric acid esters can be obtained byreacting alkyl or aryl esters of phosphoric acid with phosphoruspentoxide whereby oily compounds are formed which cannot be distilled.This process has the disadvantage that the unreacted proportions of thestarting products can be separated from the reaction product only withdifliculty at elevated temperatures. At temperatures above 120 C.,however, neutral polyphosphoric acid.

esters, except methyl esters, begin to decompose. The said process isnot, therefore, suited for the manufacture of.

polyphosphoric acid esters that are free from phosphate and phosphoricor polyphosphoric acid. It is furthermore known that tetrameric cyclicpolyphosphoric acid esters are formed by the reaction of phosphoruspentoxide with diethyl ether in chloroform. In this process, a definitemixture of two known compounds is formed; the reaction requires,however, a relatively long time, which is inconvenient especially forthe manufacture of relatively large amounts of these polyphosphoric acidesters. Moreover, the course of the reaction depends to a large extenton the quality of the phosphorus pentoxide used.

Now we have found that derivatives of polyphosphoric acid esters can beobtained in an advantageous manner by ice reacting nonmetallic acidesters of nonmetals of Groups III, IV and VI of the Mendeleeif PeriodicTable or mixtures of these nonmetallic acid esters, if desired in thepresence of a solvent, at a temperature within the range of 78 C. and C.with phosphorus pentoxide.

The term nonmetallic acid esters is used herein to mean compounds of theelements boron, carbon, silicon and sulfur which correspond to one ofthe following Formulae I to IV.

(Hammett). R .0 OR

in which R represents a saturated or unsaturated, oxalkylated orhalogenated aliphatic radical or an aromatic radical, R and R eachrepresent a saturated or unsaturated, oxalkylated or halogenatedaliphatic or cycloaliphatic radical or an aromatic radical. In FormulaII, R may also represent a hydrogen atom. R, R and R7 may be identicalor different and may each contain 1 to 12 carbon atoms. As oxalkylatedaliphatic radicals there are advantageously used methoxy, ethoxy,propoxy or butoxyalkyl radicals. As halogenated aliphatic radicals,mono-haloalkyl groups may be advantageously used. Furthermore, in theabove Formulae I to IV, j, k, l, m and n are whole numbers or zero andmust be such that the equations given below the said formulae befulfilled, and n must be greater than zero in Formulae I, II and IV; inFormula III x is a whole or fractional number of at least one.Fractional numbers are obtained when, in the case of polyorthosilicicacid esters, mixtures of such esters are used for the reaction.

Nonmetallic acid esters suitable for use in the process of the inventionare, for example, B(OR) R B(OR) R'RBO'R, C(OR) 'HC(OR) Si(OR) R'Si(-O-R)RRSi (OR -R SiOR, (R0) SiO-Si(OR OS(OR) and RSO (OR) in which R, R andR" have the meanings given above.

Nonmetallic acid esters particularly suitable for use are, for example,compounds of the formula R'RSi(OR) in which R, R and R represent methylor ethyl groups, or mixtures of such compounds. There may further beused hexa-ethyl-di-orthosilicate and ethylpoly-orthosilicate. It is alsopossible to use trimethyl, triethyl or tripropyl esters of orthoboricacid or the corresponding esters of alkylboric acids in which the alkylgroup contains 1 to 4 carbon atoms, or mixtures of such compounds forthe reaction with phosphorus pentoxide.

The nonmetallic acid esters are added in a pure state or in the presenceof one of the solvents indicated below at a temperature within the rangeof 78 C. to +140 C., advantageously 30 C. to +100 C., preferably underan inert gas, for example nitrogen, and with as complete an exclusion ofmoisture as possible, to phosphorus pentoxide in a pure state or in theform of a mixture thereof with one of the solvents named below. Thereaction mixture so obtained is stirred or vigorously mixed thoroughlyat a temperature within the range indicated above. The reaction timedepends on the reactivity of the nonmetallic acid ester and the reactiontemperature and varies within a few minutes (about 3 to minutes) andabout 48 hours. The nonmetallic acid ester is advantageously used in amolar ratio within the range of 0.005 to moles, advantageously the molaramounts set forth in the table given below for each mole of phosphoruspentoxide.

In the first column of the table, the type of nonmetallic acid esterused is indicated, R, R and R having the meanings given above. Thesecond column indicates the range of the molar amounts of thenonmetallic acid esters within which the nonmetallic acid ester isreacted, for example, with 1 mole of phosphorus pentoxide.Polyorthosilicic acid alkyl esters, in which the alkyl groups may rangefrom methyl to n-pentyl groups, are used in an amount of 0.25 to 3 unitsof weight for each unit of weight of phosphorus pentoxide.

TABLE Type of nonmetallic Range of molar amounts of nonacid ester:metallic acid ester/ mole P 0 B(OR) 0.05-3 RIB(OR)2 0.1-5 R'R' BOR 0.2-9C(OR 0.02-2.5 HC(OR) 0.05-3 RC(=OR) 0.0s 3 Si*(OR) 0.022.5 (RO)SiOfi'Si(OR) 0.0l-2.0 RSi(OR) 0.05-3 tRRSi(OR) 0.1-5 R SiOR 0.2-9 OS(OR) 0.05-5 R'SO OR 0. 2-9

As solvents, halogenated hydrocarbons boiling between C. and 120 C. maybe used. Advantageously chloroform, methylene chloride or1,1,1-trichlorethane are used. It is, however, also possible to carryout the reaction in the presence of, for example, carbon tetrachloride,methylene bromide, symmetrical or asymmetrical dichlorethane,1,1,2-trichlorethane, trichlorethylene, tetrachlorethylene,trifluorotrichlorethane or symmetrical difiuorotetrachlorethane ormixtures of these compounds. The solvents are advantageously used in ananhydrous or alcohol-free state in an amount within the range of 1 to300 parts by weight, advantageously 7 to parts by weight, for each partby weight of phosphorus pentoxide.

It is advantageous to carry out the reaction and also the work-up withas complete an exclusion of moisture as possible.

The polyphosphoric acid ester derivatives formed are obtained after thereaction in the form of a solution or, if the reaction is carried outwithout a solvent, in the form of viscous oils intermingled withunreacted P 05. In the latter case it is advantageous to dissolve theoils by adding a solvent since solutions can be worked up particularlywell. The solutions can be separated from the solid substance by suctionfiltration and freed from solvent and unreacted nonmetallic acid esterunder reduced or strongly reduced pressure at a temperature of the bathof below 110 C. It is also possible to precipitate the dissolvedpolyphosphoric acid ester derivatives by adding a liquid precipitatingagent. The supernatant solvent containing the unreacted proportions ofstarting CPI product and other impurities, is decanted. This procedureof dissolving and precipitation may be repeated as often as desired toremove undesirable impurities substantially quantitatively from thepolyphosphoric acid ester derivatives. As precipitating agents, lowmolecular weight alkanes and cycloalkanes with S to 12 carbon atomswhich are liquid at room temperature may advantageously be used.Examples of such compounds are hexane, heptane, octane and cyclohexane.Aliphatic or cyclic ethers, for example, diethyl ether,tetrahydrofurane, glycol dimethyl ether, dioxane and benzene may also beused as precipitating agents. The nonmetallic acid esters are in generalsufficiently soluble in the organic solvents used as precipitatingagents and are highly soluble in the solvent mixtures comprisinghalogenated hydrocarbons and precipitating agents, which are formed inthe precipitating process. The precipitation of dissolved polyphosphoricacid ester derivatives may also be used for fractionating the productsby precipitating fractions with ditferent'degrees of solubility oneafter the other by adding different amounts of precipitating agent.Fractions that have been obtained in this manner differ from one anotherwith respect to their catalytic activity. The polyphosphoric acid esterderivatives are obtained in the form of a colourless to slightlyyellowish viscous oil which cannot be distilled or in the form of anamorphous solid mass.

The polyphosphoric acid ester derivatives constitute mixed anhydrides ofpartially hydrolyzed polyphosphoric acid esters with partially orcompletely hydrolyzed nonmetallic acid esters. These mixed anhydridescontain a mixture of open-chain, cyclic and combined open-chain/ cyclicmolecules with polyphosphate structures in whichphosphorus-oxygen-nonmetal bonds are statistically distributed. Thecontent of such P-O-nonmetal groupings depends chiefly on the molarratio in which the starting products have been reacted with one another.It is, however, also infiuenced by the reaction temperature and dependsalso on the individual nonmetals themselves. The nonmetal atom in themixed polyphosphoric acid ester anhydrides may be linked to phosphorusatoms via all single-bond oxygen functions present in the nonmetallicacid ester or via only a part of these oxygen bonds. In the latter casethe remaining nonmetal-oxygen-single bonds still carry the radicalspresent in the starting ester. The following general formulae representtwo of the numerous possible molecule sections of such polyphosphoricacid ester anhydrides, radicals R and R having the meanings given above.

I O O 0 R O1 X=nou1netal ([5 Z+m+n=valence of r the nonmetal Thenonmetallic acid esters partially give off their OR groups only for thesplitting of the P 0 structure into neutral polyphosphoric acid esterparts, the nonmetal pardrides of the invention have a considerablyimproved catalytic action when used, instead of acids or Lewis acids, ascatalysts for proton-catalyzed reactions. Moreover, the catalytic actionof the polyphosphoric acid ester anhydrides obtained in accordance withthe invention can he graduated by means of a different content ofnonmetals other than phosphorus.

The mixed polyphosphorio acid ester anhydrides made inaccordance withthe invention can be used as catalysts for proton-catalyzed reactionssuch as, for example, biochemical polycondensation reactions orpolymerization reactions, for example, in the field of polyacetals. Theymake also appropriate intermediates for the manufacture of insecticides.

The following examples serve to illustrate the invention but they arenot intended to limit it thereto.

EXAMPLE. 1

6.97 grams (49 millimoles) phosphorus pentoxide and 20 cc. purechloroform were introduced into a groundglass flask of a capacity of 100cc., under an atmosphere of dry nitrogen and with the exclusion ofmoisture. The reaction mixture so obtained was kept on a bath having atemperature of +20 C. and 3.5 grams (24 millimoles) triethyl borate werequickly added dropwise from a pipet, while shaking. The reaction mixturewas kept for about 30 minutes on the bath having a temperature of 20 C.,while shaking occasionally. The bath was then withdrawn and shaking wascontinued for a further 6'hours at room temperature. The reactionmixture was then separated from undissolved proportions by suctionfiltration and the solution was concentrated by evaporation under areduced pressure of 3 millimeters of mercury on a bath'having atemperature of 50 C. until a constant weight was obtained. 9.3 grams ofa tough colourless glassy mass which was readily soluble in the usualchlorinated hydrocarbon were obtained.

Composition in percent: B, 3.3; P, 24.7; C, 21.4; H, 4.6.

EXAMPLE 2 Under the conditions of Example 1, 18.3 grams (125 millimoles)triethyl borate were added to a mixture of 17.82 grams (125 millimoles)phosphorus pentoxide and 40 cc. chloroform. The mixture so obtained wasshaken for 24 hours at room temperature until substantially all of thephosphorus pentoxide had undergone reaction. To facilitate filtrationthe reaction mixture was diluted with 50 cc. chloroform andsuction-filtered. The filtrate was concentrated in vacuo on a bathhaving a temperature of 50 C. 25.5 grams of a tough colourless glassyproduct were obtained.

Composition in percent: B, 3.3; P, 22.8; C, 23.0; H, 5.1.

EXAMPLE 3 12.5 grams of the colourless glassy product obtained by thereaction described in Example 2 were dissolved in 30 cc. chloroform. Tothe solution so obtained 30 cc. heptane were added while shaking,whereby a white amorphous product (fraction I) was graduallyprecipitated. The supernatant solution was decanted. The amorphousresidue was shaken with 50 cc. of a mixture of 5 parts by volume ofheptane and 1 part by volume of chloroform and allowed to deposit andthe solution was decanted. This procedure was carried out three times.The amorphous residue was freed from solvent in vacuo at a temperatureof the bath of 50 C. 7.0 grams of an amorphous solid white product whichwas very hygroscopic and deliquesced rapidly in the air (fraction 1)were obtained.

Composition in percent: B, 4.8; P, 19.7; C, 18.9; H, 4.3.

To the solution which had been decanted in the precipitation of fractionI 30 cc. heptane were added whereby further proportions of a solidamorphous product (fraction II) were precipitated. Fraction II wasworked up and washed in the same manner as fraciton I. By evaporatingthe solvent in vacuo at a temperature of the bath of 50 C., a solidamorphous mass which was deliquescent in the air was obtained (fractionH).

Composition in percent: B, 4.7; P, 8.5; C, 18.0; H, 4.8.

EXAMPLE 4 Under the conditions described in Example 1, 4 grams (21millimoles) tri-n-propyl borate were added to a mixture of 6.2 grams (43millimoles) phosphorus pentoxide and 30 cc. chloroform. The reactionmixture so obtained was heated overnight at +40 C., while stirring. Thereaction mixture was then suction-filtered and the filtrate wasconcentrated in vacuo at a temperature of the bath of 40 C. until aconstant weight was obtained. 7.3 grams of a tough slightly yellowishglassy mass which was easily soluble in chloroform were obtained.

Composition in percent: B, 3.1; P, 18.2; C, 31.3; H, 6.4.

EXAMPLE 5 In the manner described in Example 1, 8.56 grams (37millimoles) tri-n-butybborate were added to a mixture of 5.25 grams (37millimoles) phosphorus pentoxide and 30 cc. methylene chloride. Thewhole was shaken over-night at 20 C. and then worked up as described inExample 1. By evaporating under a pressure of 0.1 millimeter of mercuryat a temperature of the bath of 35 C. until a constant Weight had beenobtained, 12.55 grams of a tough colourless glassy product wereobtained. The product was very easily soluble in the usual chlorinatedhydrocarbons and in mixtures of such compounds with, for example,heptane in a proportion by volume of 1:8.

Composition in percent: B, 2.9; P, 17.7; C, 36.2; H, 7.1.

A sample heated for 10 hours at C. under a pressure of 0.1 millimeter ofmercury had the following composition as determined by analysis: B,3.1%; P, 17.8%; C, 36.0%; H, 6.9%. Consequently, the poly phosphoricacid ester derivative was not decomposed at that temperature.

EXAMPLE 6 In the manner described in Example 1, 10.5 grams (45millimoles) tris-[2-methoxyethyl1-borate were added to a mixture of 6.46grams (45 millimoles) phosphorus pentoxide and 20 cc. chloroform. Thereaction mixture acquired a slightly yellowish colouration and washeated for 24 hours at 40 C. The phosphorus pentoxide Was not dissolvedcompletely. The reaction mixture was suction-filtered and the solutionwas concentrated to about 15 cc. 60 cc. heptane were added whereby acolourless oil was precipitated. The supernatant solution. was poured01f and the oil remaining behind was digested twice with 50 cc. of amixture of 5 parts by volume of heptane and 1 part by volume ofchloroform. The residual proportions of solvent were removed by heatingin vacuo at 40 C. 6.2 grams of a colourless amorphous mass wereobtained.

Composition in percent: B, 3.6; P, 8.4; C, 36.3; H, 7.4.

EXAMPLE 7 Under the conditions described in Example 1, 13.8 grams (47.5millimoles) triphenyl borate were added to a mixture of 6.77 grams (47.5millimoles) P and 30 cc. chloroform and the whole was heated for 24hours at 80 C. The reaction mixture was then separated from the brownsolid substance by suction filtration. The solution was concentrated tocc. and 100 cc. heptane were added. A yellowish oil precipitated which,after decantation of the supernatant solution, was washed and freed fromsolvent in vacuo as described in Example 6. 16.2 grams of a yellowishamorphous mass were obtained.

Composition in percent: B, 3.0; P, 12.9; C, 50.2; H, 4.1.

EXAMPLE 8 2.93 grams (l6 millimoles) triallyl borate were added at C.,under dry nitrogen, to a mixture of 5.10 grams (36 millimoles)phosphorus pentoxide and cc. chloroform and the whole was shaken at 0 C.for 48 hours. The reaction mixture acquired a brown colour; the reactionwith P 0 was incomplete since the P 0 was superficially covered withsmall amounts of resinous by-products which formed and thus impeded afurther reaction. The reaction mixture was suction-filtered and thesolution was concentrated in vacuo to 20 cc. and admixed with 90 cc.heptane. A yellow brown oil precipitated. It was washed and freed fromsolvent as described in Exmaple 6. 4.1 grams of a brownish viscous oilwere obtained.

Composition in percent: P, 11.1; C, 35.5; H, 5.6.

EXAMPLE 9 7.3 grams (50 millimoles) triethyl borate and 11.5 grams (50millimoles) tri-n-butyl borate were added to a mixture, kept at l0 C.,of 10.32 grams (75 millimoles) phosphorus pentoxide and 50 cc. methylenechloride. The phosphorus pentoxide dissolved completely within a fewminutes. After having been kept at 10 C. for about 30 minutes, thereaction mixture was shaken for a further 3 hours at room temperature.The reaction mixture was then concentrated under a pressure of 0.1millimeter of mercury at a temperature of the bath of C. until aconstant weight was obtained. 17.9 grams of a viscous colourless oilwere obtained.

Composition in percent: B, 3.6; P, 18.3; C, 25.7; H, 5.6.

EXAMPLE 10 Under the conditions of Example 1, 1.53 grams (15 millimoles)ethylboric acid dimethyl ester were added to a mixture at 0 C. of 4.25grams (30 millimoles) phosphorus pentoxide and 10 cc. methylenechloride. After 30 minutes the temperature of the reaction mixture wasallowed to rise to room temperature and the reaction mixture was shakenat that temperature for 4 hours. The reaction mixture was then separatedfrom undissolved proportions by suction filtration and the solution wasconcentrated as described in Example 9. 4.6 grams of a viscouscolourless oil were obtained.

Composition in percent: B, 2.7; P, 25.3; C, 22.3; H, 4.9.

EXAMPLE 1 1 In the manner described in Example 10, 1.78 grams (10millimoles) phenylboric acid diethyl ester were added at 0 C. to amixture of 5.37 grams (38 millimoles) phosphorus pentoxide and 30 cc.methylene chloride and the whole was shaken vigorously. After 10minutes, the temperature of the reaction mixture was allowed to rise toroom temperature and the reaction mixture was shaken at that temperaturefor a further 6 hours. The reaction mixture was then diluted with cc.methylene chloride and separated from undissolved proportions by suctionfiltration. The solution was concentrated in vacuo to about 10 cc. and70 cc. hexane were added, whereby an amorphous white product wasprecipitated. The latter was washed like the solid fractions describedin Example 3 and freed from residual proportions of solvent by drying invacuo at a temperature of bath of C.

The product contained 1.3% of boron.

EXAMPLE 12 2.13 grams (l1 millimoles) tetraethyl orthocarbonate wereadded dropwise under nitrogen, while stirring, to a mixture at 30 C. of3.14 grams (22 millimoles) phosphorus pentoxide and to 10 cc.chloroform. After 10 minutes, the temperature of the reaction mixturewas allowed to rise to room temperature and the mixture was then heatedfor 4 hours at 60 C. The reaction mixture was separated from smallproportions of unreacted P 0 by suction filtration and the solution wasthen evaporated under a pressure of 0.1 millimeter of mercury at atemperature of the bath of C. until a constant weight was obtained.About 4 grams of a viscous colourless oil were obtained.

Composition in percent: P, 27.7; C, 22.1; H, 4.9.

EXAMPLE 13 Under the conditions described in'Example 12, 9.32 grams (63millimoles) triethyl orthoformate were added to a mixture of 8.96 grams(63 millimoles) phosphorus pentoxide and 40 cc. chloroform. After 10minutes the reaction mixture was heated for 6 hours at 40 C. Thephosphorus pentoxide dissolved completely. The solvent was evaporated invacuo at a temperature of the bath of 60 C. A colourless oil wasobtained.

Composition in percent: P, 25.8; C, 23.3; H, 5.1.

EXAMPLE 14 1.33 grams (9 millimoles) triethyl orthoformate were added toa mixture at 0 C. of 6.34 grams (44.5 millimoles) phosphorus pentoxideand 30 cc. carbon tetrachloride. The temperature of the reaction mixturewas allowed to rise to room temperature within 15 minutes. The reactionmixture was then shaken for 10 hours at room temperature and thenseparated from unreacted proportions of phosphorus pentoxide by suctionfiltration. The solution was concentrated under a pressure of 0.1millimeter of mercury at a temperature of the bath of 40 C. until aconstant weight had been obtained. A viscous oil was obtained.

Composition in percent: P, 37.3; C, 22.6; H, 4.9.

EXAMPLE 15 Under the conditions described in Example 12, 22.7.

grams (154 millimoles) triethyl orthoformate were added to a mixture of7.32 grams (51.5 millimoles) phosphorus pentoxide and 10 cc. methylenechloride. The temperature of the reaction mixture was allowed to rise to0 C.

10 grams (49 millimoles) tetraethyl orthosilicate were added dropwise toa mixture at 0 C. for 14.2 grams millimoles) phosphorus pentoxide and 20cc. chloroform under dry nitrogen. During the introduction of thetetraethyl orthosilicate, the mixture was cooled on an ice wa-' terbath. The reaction was strongly exothermic. The P 0 had reacted within afew minutes. A viscous solution containing insoluble proportions wasobtained, which was diluted with 200 cc. chloroform to facilitatefiltration. The

reaction mixture was suction-filtered and the solution was concentrated.A soft amorphous crumbly product was obtained. The product wascomminuted, 200 cc. of a mixture of 2 parts by volume of heptane and 1part by volume of chloroform were added and the whole was shaken for 6hours. After suction filtration, the solid amorphous white filtrate wasfreed from solvent in vacuo at a temperature of the bath of 80 C. Awhite amorphous mass (fraction 1) was obtained.

Composition in percent: Si, 3.7; P, 19.7; C, 24.7; H, 5.9.

The solid residue left behind in the first suction filtration of thereaction mixture was also comminuted, washed and freed from solvent asdescribed above. A white amorphous mass (fraction II) was obtained.

Composition in percent: Si, 8.1; P, 18.2; C, 11.0; H, 2.6.

Fraction I was sparingly soluble and fraction II difficultly soluble inchloroform.

EXAMPLE 17 4.0 grams (11.5 millimoles) hexaethyl-di-orthosilicate wereadded to a mixture at 20 C. of 4.70 grams (33 millimoles) phosphoruspentoxide and 20 cc. chloroform and the whole was shaken at roomtemperature for 6 hours. A transparent stifi gel was obtained; the P hadbeen consumed quantitatively. The chloroform was evaporated in vacuo. Awhite amorphous mass which was easily soluble in chloroform wasobtained.

Composition in percent: Si, 7.6; P, 21.4; C, 22.3; H, 5.2.

EXAMPLE 18 6.6 grams ethyl polyorthosilicate were added to a mixture at20 C. of 8.07 grams (5 8 millimoles) P 0 and 20 cc. chloroform and thewhole was shaken for 6 hours at room temperature. The gel-like masswhich had been formed (the P 0 had been consumed quantitatively) wasconcentrated in vacuo. A white amorphous mass was obtained which waseasily soluble in chlorinated hydrocarbons.

EXAMPLE 19 6.3 grams (52 millimoles) dimethyldimethoxysilane [(CH Si(OCHwere added dropwise, while stirring, under dry nitrogen to a mixture at20 C. of 7.45 grams (52 millimoles) P 0 and 20 cc. chloroform. After 20minutes the temperature of the reaction mixture was allowed to rise toroom temperature. The phosphorus pentoxide reacted quantitatively. Thesolvent was evaporated in vacuo at a temperature of the bath of 40 C.until a consant weight was obtained. A viscous colourless oil wasobtained.

Composition in percent: Si, 9.3; P, 22.7; C, 16.0; H, 4.3.

. EXAMPLE 20 Under the conditions described in Example 19, 1.44 grams(l2 millimoles) dimethyldimethoxysilane were added to a mixture of 6.74grams (47.5 millimoles) phosphorus pentoxide and cc. methylene chloride.After 10 minutes the temperature of the reaction mixture was allowed torise to room temperature and the reaction mixture was shaken for afurther 5 hours. It was then diluted with cc. methylene chloride andseparated from undissolved proportions by suction filtration. 50 cc.heptane were added to the solution whereby an oily colourless productwas precipitated. The supernatant solution was decanted and the oil waswashed and freed from residual proportions of solvent in vacuo asdescribed in Example 3. An amorphous solid white mass was obtained.

10 Composition in percent: Si, 6.2; P, 32.8; C, 12.4; H, 3.2.

EXAMPLE 21 14.2 grams millimoles) dimethyl sulfite were added, undernitrogen and with the exclusion of moisture, to a mixture of 18.34 grams(130 millimoles) phosphorus pentoxide for 6 hours at 60 C. The reactionmixture was separated from unreacted phosphorus pentoxide by suctionfiltration. The solution was concentrated in vacuo at a temperature ofthe bath of 80 C. until a constant weight was obtained. 20.2 grams of aviscous colourless oil were obtained.

Composition in percent: S-; P, 31.4; C, 14.3; H, 3.7.

EXAMPLE 22 In the manner described in Example 21, 7.64 grams (54millimoles) phosphorus pentoxide and 3.58 grams (32 millimoles) dimethylsulfite were reacted in the presence of 10 cc. chloroform. After heatingfor 6 hours at 60 C., the reaction mixture was cooled to roomtemperature and 60 cc. of heptane were then added. The oil which hadprecipitated was washed and freed from residual proportions of solventas described in Example 6, a viscous colourless oil being obtained.

EXAMPLE 23 19.2 grams (175 millimoles) methanesulfonic acid methyl esterwere added, under nitrogen and with the exclusion of moisture, to amixture of 12.4 grams (87.5 millimoles) phosphorus pentoxide and 10 cc.methylene chloride, and the whole was heated under reflux for 5 hours. Afurther 20 cc. methylene chloride were then added and the solution wasseparated from the solid substance by suction filtration. The filtratewas concentrated to about 10 cc. in vacuo and 50 cc. absolute ether werethen added, whereby a yellowish oil was precipitated. The oil wasallowed to deposit and the supernatant solution was decanted. The oilwas digested twice with 50 cc. absolute ether and then free under apressure of l millimeter of mercury at a temperature of the bath of 50C. from residual solvent. 18.3 grams of a yellowish viscous oil wereobtained.

Composition in percent: S, 16.8; P, 19.0; C, 12.2; H, 3.2.

We claim:

1. A process for producing neutral polyphosphoric acid ester derivativeswhich comprises reacting an acid ester with phosphorus pentoxide at atemperature within the range of --78 C. to C., in the absence ofmoisture and in a mole ratio of ester to phosphorus pentoxide from 0.02to 3 moles ester to 1 mole phosphorus pentoxide, said acid ester beingdefined by the formula wherein m-+n=4, and in which formula R representshydrogen or alkyl of 1 to 2 carbon atoms and R represents alkyl of 1 to2 carbon atoms.

References Cited Brannock: Jour. of Am. Chem. Soc," vol. 73, pp. 4953-4(1951).

CHARLES E. PARKER, Primary Examiner A. H. SUTI'O, Assistant ExaminerU.S. C1. X.R.

v UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 161-2356 Dated February 15, 1972 Inv n fls) Kampe and Fischer It iscertified that error appears in the above-identified patent and thatsaid Letters Patent are hereby corrected as shown below:

In the Heading:

After "am Main, Germany" insert assignors to Farbwerke HoechstAktiengesellschaft vormals Meister,

Lucius 8c Bruning, Frankfurt am Main, Germany Signed and sealed this 8thday of August 1972.

(SEAL) Attest:

EDWARD M.FLETCHER,JR ROBERT GOTTSCHALK Attesting Officer Commissioner ofPatents FORM PO-105O (10 69) USCOMM-DC 60376-P69 u.s. GOVERNMENTPRINTING OFFICE: I969 o-zss-aan

